Contbol systejtt fob electric motoks



BESTAVAILABLE -LH. THULLEN. CONTROL SYSTEM FOR ELECTRIC MOTORS.

APPUCATION FILED JAN. 10' 1914.

ATTORN w Patented Dec. 2, 1919.

LOUIS n. THULLEN, or Pinmnnnrms, PENNSYLVANIA.

common sirsrrn u r03 ELECTRIC MOTORS.

I Specification of Letters Patent.

Patented Dec. 2, 1919.

Application filed January 10', 1914. Serial No. $11,299

To all whom it may concern:

Be it known that I, LOUIS H. THULLEN, a citizen of the United States,residin in the city and county of Philadelphia, tate of Pennsylvania,have invented a novel Control System for Electric Motors, of

which the following is a specification.

My invention relates to a novel means or system of automatically.controlling alternating current, electric motors, and has particularieference to the control'of alternatingcurrent motors, when used inconnection with feed carriages for friction saws or analogous mechanismhaving a moving table, or where the motor has a varying load or issubject to periodical heai'y overload alternatin with light or no load.

General y, an alternatin current motor has a pull-out torque, of a outtwo and a half times its normal rating. It is quite often desirable tooperate such a motor periodically at four to five times its normalrating, and in order to accomplish this, I

have devised a novel means whereby,durmg short periods of overload, avoltage higher than normal can be impressed upon the motor, therebyincreasing the pull-out torque, as the pull-out torque of a motor is inproportion. to the-second power of the applied voltage. In connectionwith this,

I use a means, whereby when the motor is.

running idle, or at light load, normal voltage is impressed on themotor. It is also possible to so build a motor that the pullout torquewill .be in excess of two and a half times the pull-out torque of astandard motor, but when a motor is designed in this manner, it iseither excessively large, has a large magnetizing currentorthe magneticcircuit is operated at a very high density. To use a motor designed inthis way, it is desirable to apply a x 'oltage lower thannormal duringlight loads or when running empty, and my novel means for doing thisconstitutes the object of said invention.

To the above ends my invention in its broad aspects consists of thenovel combination of an electric motor, a starting transformer therefor,and a novel means in connection with said starting transformer to applyhigher than line voltage to said motor.

It further consists. of a novel con'ibination of a starting means. atransformer, fuses and a novel arrangement of circuits, which tion, Ihave shownin the accom 'riously arranged and organized is capable ofgeneral application, 'but is especially applicable to the controlofalternating current motors used in connection as a feed carriage forfriction saws, or where the motor has a varying load. 1

For the purpose of illustrating my inven- I anying drawmgs one .formthereof whic is at with mechanism having a moving element,

present preferred by me, since the same will be found in practice togive satisfactory and reliable results, although it "is to e understoodthat the various instrumen lities of which my invention consists be ,va-

and that my invention is not limited to the precise arrangement and'organization of these in s'trumentalities as herein shown and dcscribed. 4

Figure 1 represents a perspective view of a friction saw or analogousmechanism equipped with a novel, control system embodying my invention,two controllers being shown diagrammatically with the neces: sarystarting transformer and the fuse cutout device.

Fig. 2 represents diagrammatically a. controller so arranged and builtthat. a higher than normal voltage can be applied to an alternatingcurrent motor when one set of fuses only are used- Eig. 3 represents ahandle and itsads juncts to be used in connection with the controll'ershown in Fig. 2, and so arranged that after the motor reaches normalspeed at normal voltage, a. latch can be released and. the controllerthrown in position ofhigher than normal voltage, but must .he he (1there manually, and if the hand is removed from the controller, thecontroller will immediately go back to the normal voltage position. Fig.4 represents one phase of a controller which is used in connection witha motor that is so designed that its normal voltage is at less than linevoltage, and when operating at linew'oltage, the starting trans formeris cut out. r

Similar numerals of reference indicate corresponding parts in thefigures. Referring to the drawings Referring to Fig. 1, 1 designates thebed' or housing of a sawing or analogous mechanism. 2 the carriage orreciprocating part, on which is mounted the saw or duty mofor 3, and onthe end of whose shaft revolves the disk or saw 4. The feed motor 5 isused to reciprocate the table 2 backward. and forward by means. of theworm 6 and the gears 7 and'8 which lattermeshes with a suitable .mk. inthis figure, h shown a three-phased motor, but it is well understoodthat in this art,-a motor of any number of phases can be for this a P Inconnection with the motor'--3, 9," 10 and 11 designate three terminalsfor the 1 are a source of three-phased alternating currents and fromthis source areconnected cables 21, 22 and 23, respectively,'. which.lead to segments 24, 25 and 26of the con troller 43. Cables 27 28 and29. are also attachedto the cables 21, 22 and 23', respec tively, andlead to the controller points-30,

31 and 32, respectively, through the medium of fuses 33, 34 and 35,while from said fuses 33, 34 and 35 are also taken the'cables 36," 37and 38, respectively, which go to thefl -seg ments 39,40 and 41. p 44diagrammatically shows a starting either get a higher than normalvoltageor can operate the motor at a point lowerthan' normal. 'In thetransformer 44, I here show;

,, a tap 45 which, in this case,-applies normalvoltagewhenjthe-controller is in the extreme left position and contact is made"with the contact 46 with thecontroller segment 24-,

and the current is then applied to the transformer for the one phasethrough the'cable 21 from the onemam 18 of a source of alternatingcurrent supply. 5-

When the controller 43 is this position, current is also supplied to theother two phases in the following manner, from the main 19 of thesourceof supply through thecable 22, controlle segment 25, contact 47,tap 48 to the other Ev former, and for the other p ase, through themedium of main-20 from thesource of supply, cable 23, controller segment26, con: tact 49 and tap 50 to the third winding of the startintransformer 44. When the controller ism this position, contact is madebetween segment 51 and contact 52, s ment .58 and contact54, and segment55 an contact 56'," whereb current at a reduced voltage is impresse.upon the lines or cables 57 .58 'and 59, to the contacts 60, 61 and 62of controller 42. It can be readily seen thatwhen the controller 43 isin this position, that normal voltage is applied to the start in'transformer, and lower than normal vo tags is applied to the motor 36;start .ment 16 is incontac't with contact th controllers are in thisposition when 1 the motor 3 is started, as it is well known to, thoseskilled-in this art, that it is desirable 42 is in the extr the table 2reacf indin of the transsame when the controller is in the extreme rightposition. Whenthe controller 42 is in the extreme right position, lowvoltage is 1 -1s incontact with contact finger seg finger 61, andsegment 15. in contact with contact a plied tothe motor 3, as follows,-'-segment to start analternating current motor at less thannormah'voltage.

After ,motor '3 has attained pproximately 'normalspeed, the controller.43 -is shifted tothe right, 'at which time contact segment "51asincontact v.with contact finger 30, controller segment 53- is incontact with contact finger 31,,iand controller segment- 55 is incontact w th contact fin er 32. :..The-movement-to the; right thereoreconnects motor .3 to the mains 18, 19 and 20-directly with out themedium of transformer 44, and-normal voltage isapplied to said motor.

63 designatesthe shaft that operates the cylinder or controller 42 .Onthe end of the shaft; 63 is a gear Two projections 65 .jand 66, not inthe sameplane, are fastened to a gear .64 which meshes with gear 64.transformer forthe motor 3, and in this starting transformer, I also'use asecond, winding, or so arrange" the taps that"-I can Projections.65.an l 66 are here shown in the position. they .assume whenthecontroller me right position. When ics 1ts extreme osition tothe'.right, at which time it is esirable to apply a higher thannormal-voltage to-the motor 3, the lug or tappet 67', carried by saidcable comes in contact with the projection 65, and the-projection-65- is-moved'to a horizontalposition and the controller cylinder 42 is movedto the extreme left, thereby causing thesegment 39 to come in contactwithcontact finger 6?, controller segment 40 h to come in contact wicontact finger 69, and controllerscgment 41 to contact with contactfinger 70, and-segments15', 16 and 17 in engagement with contacts 128,125 and 124, respectively. This brings the motor 3 in connectionwith-tho high volta e "tap on the transformer taps 71, 72 and 73 of thetransformer 44 through the medium of cables 75, 76 and 77, respectively,andv also brings segments 142143 and 144 into engagement with contacts130, 131'and-132,

respectively, to reverse motor 5. When the table 2 reaches the extremeleft point of travel, the lug or tappet 78 on the table 2 comes incontact with the projection 66, thereby moving the controller 42 to theextreme right 'position, impressing normalvoltage on themotor 3- andagain reversing the motor 5. Normal voltage remains on themotor 3 untilthe table is moved to the exiao tacts 127, 128 and 129 on the other sideof the controller 42, constitute the reversing switch for the motor 5.When the segments 142, 143 and 14% are moved to the right, the motor 5runs in one direction, and' and the shaft 63, in a manner which will becircumstances.

readily appreciated .from an inspection of the drawings. A switch 200 isprovided for connecting or disconnecting the reversing switch to theline through the branch contacts 201, 202 and 203.- This switch operatesin the well-known manner.

The tappets 67 aiid 78 are adjustable on the carriage 2 so that thepoints of reversal of the feed motor 5, and the increase or decrease ofvoltage being impressed on the duty motor 3, may be changed to suit theIt is desirable that the increased or abnormal voltage be applied to themotor 3 a substantial length of time before the work carried by thecarriage 2 is presented to the saw. This is desire le for the reasonthat the saw has considerable inertia and should be permitted to bebrought up to full speed before it comes in contact with the work. It isevident that by properly placing the tappet 67 so as to increase thevoltage on the duty motor while the work is a substantial distance awayfrom the saw, the saw will be brought up to full speed before the motor5 can be reversed and bring the work which is upon the carriage 2 incontact with the saw.

It will be noticed that in this i1ivention,I make us of an auxiliarywindingon the starting transformer for obtaining a high er than normalvoltage, by which means I save a separate transformer and by puttinginor connecting another winding, I utilize the starting transformerwhichis av less cxpensive transformer than a regular one, as it is only incircuit part of the time, and therefore can be built with less copperand iron. The controllers 42 and 43 may be combined into a singlecontroller and still come within my invention.

In Fig. '2, I have diagrannnatically shown a controller operated by thehandle seen in Fig. 3. 3 designates the same motor as shown in Fig. 1,but diagrammatically illustrated. 18, 19 and 20 designate a source ofthree-pliase alternating current supply, the cables 21, 22 and 23 beingconnected there to, as already described with respect to Fi 1. From thecables 21, 22 and 23 arelea s 27, 28 and 29 attached to the fuses 33, 34and '35, to which are attached leads 36, 37 and 38, and connected to thecontact fingers 30, 31

and 32, substantially as already described.

44 is an auto transformer, similar to that shown in Fig. 1, theconnections and taps also being similar. When the handle shown in Fig. 3is moved to the extreme left, the controller is revolved to the left insuch a manner that segment 7 4 makes contact with contact finger 46,thereby applying line voltage to one phase of the transformer 44. At

tactwith contact fingers 54 and 56, thereby impressing less than linevoltage on motor 3, throu h the medium of cables 81 and 82. \Vhen t econtroller is in this position, which is thestarting position, less thanline voltage is applied to the motor in a manner.

well known to those skilled in theart, as is evident. Y

Referring now particularly to Fig. 3, it will be seen that when thecontroller is in this position, the latch 83 is depressed against thespring 84, moving the piston in dash pot 85, which may be of anyconventional type, downwardly. The handle, which is in its off positionas seen in Fig. 3, is first moved to the left and is then quickly movedto the right until the latch 83 comes against the stop 86. Thisparticular-cycle of the controller'handle is known in this art, and perse forms'no part of my invention. position to the right, of that seen inFig. 3, and the latch 83 is against the stop 86, the

- controller, as shownin Fig. 2, is also moved 31 and 30,. respectively,thereby impressing full line voltage on the motor 3, through the mediumof. cables 27, 28 and 29, fuses 33, 34 and 35, cables 36, 37 and 38,connections 90, 91 and 92, and cables 78, 81 and 82.

When it is desirable to impress higher than normal voltage, or a highervoltage than when the latch 83 of the controller handle is against stop86, as above described, the button 93 is pressed downwardly, therebyengaging the end of the rod 94 with latch 95, which in turn depresseslatch 83, and makes it possible to move the controller handle stillfarther to the right andagainst the tension member 96. When the handleseen in Fig. 3 is in this extreme right hand position, the controller ismoved still farther to the right, so that segment 97 makes contact withboth contact fingers 32 and 98, (see When the handle occupies a- Fig.2), therebymaking a path for one 101 and cable 78. Simultaneously withthis,

- throug I (see Fig. 2), It w.

)hase of the current throughthe fuse 35, lead 38, contact 97, cable 99,and impressing normal or line voltage on one windin of the transformer44, as was done when t e controller was vin the position to the left;Simultaneously with this, the segment 77 makes contact with contactfiuger 100, thereby impressing h'i her than normal voltage-- on themotor 3, rom the one phase of the.

transformer 44 through the medium of cable the other two segments 79 and80 make contact with contact fingers 102 and 103, thereby impressinghigher than normal voltage two phases from the transformer 44 on themotor 3, through the medium of cables 104 and 105, gird cables 81 and82,

the same time, segments 106 and 107 make contact with the contactfingers 31 and 108,

impressing line voltage on one winding of the transformer 44, and theother winding of the transformer 44 by making connections betweencontact fingers and 109.

It will also be noticed that when the controller is moved to the extremeright hand position and beyond notch 86, the controller segments 87, 88and 89 disengage with the contact fingers 32, 81 and 30. Itlwill also benoticed that the fuses 33, 34 and 35 are in the circuit path, when thelatch 83 of the controllerhandle 110 shown in Fig. 3, is pressed againstthe notch 86, and also when said controlleris at its extreme righthandposition; It will be noticed, referring to be removed "from handle 110,said handleig. 3, that it is necessary to keep'hold of the handle 110,which tends to be thrown to the left on account of the tension of thecompression'member -96. Should the hand celerated as the load increasesor decreaseson motor 3, the resultant action being substantially asdescribed in my previous Patent, No. 1,070,638.

Referring now to Fig. 4, 18, 19 and 20 designate mains which are asource ofcur rent supplty, and 21, 22 and 23 designate taps there rom,while 27, 28 and-29 designate branch taps leading to-the fuses 33, 34

and 35. The transformer starteris shown by 44. For sim licity only,connections to one phase of thls controller is shown, the other phaseshaving similar connections.

When the controller is to the left or in starting position, one phase ofthe transformer is connected to one phase 20 of the continuousconnection.

be noticed that at circuit; At t T V LABLE op,

source of current supply through the tap 25,. contact-finger 46, segment24 and tap 23.

After the motor attains speed, the controller is then guickly shifted tothe right v or at a point 0 are operate ous operation, so I here connectthe source of supply to a connection on the winding so that more of thewinding of the transformer is in circuit, thereby operating the ironcore of the transformer at the roper density for it the same time,

at too high a density with nor- -mal winding of the transformer forcontinuthe motor is also connected to a different tap to give the ropervoltage for the same, which 1s lower t an line voltage. When thecontroller is in this position, theeurrent is from the line 20 throughthe tans 28- and 29, fuse 33, line 36, contact finger 30, Segment 97,contact finger 98 and tap 101, to one phase ofthe st-artin transformer44. Simultaneously with t is, connection is made at a lower voltagepoint of the transformer with'the motor through the tap150, contactfinger 151, segment 152, connection 153, and mm 155, to one phase of themotor 3.

4 When it isjdesiredto operate the motor at heavy overload 'and at ahigher voltage than which it is. normally designed to operatecontinuously,the controller is moved to the extreme right hand position,at which time the motor 1s directly connected to the source of currentsupply-and the transformer out of is time, controller segment 154 makescontact with contact finger 30, and

segment 97 isdisconnected from contact fingers 30 and 98.1 f

' It will now be apparent that I have devised a novel and usefulconstruction of a control system for electric motors, which embodiesthe'features of advantages enumerated as desirable in the-statement ofthe invention and the above description, and while I have,-in thepresent instance, shown and described a preferred embodiment thereofwhich-will be found in practice to give satlsfactorv and reliableresults, it is to be un-v derstood that the same is susceptible ofmodification in various particulars without departing from the spirit orscope of the invention or sacrificing any of its advantages.

Havingthus described my invention, w I claim as new and desire to secureby Letters Patent, is

. 1. The combination of a plurality of electric motors, one of whichoperates under varying load-and the other of which is reversible, acontroller therefor, automatic means for applying one voltage to thevarying load motor when the other motor is ,run-' ning in one directionand for reversing the names:

other motor and applying a different voltage to the varying load motorwhen the second motor is operating in the reverse direction.

2. The combination ofla plurality of electric motors, one of whichoperates under varying load, a controller-therefor, means for applyingnormal voltage to the varying load moton when the other motor is running-in one direction andautomatic means for revers' the direction of thesecondmotor and app ying abnormal voltage to the varying loa motor whenthe second motor is opin the reverse direction. 3. fi1e combinationof-aplurality of electric motors, one of whichv operates under load,acontroller therefor, means vary for a gglying one voltage to thevarying load motor when the other motor is runmng in one direction,meansfora plying different second motor is operating in the voltage tothe varying loa motor when the o posite di rection and meansfor stoppingfile second motor. g

*4, The combination of a meter, 1;" saw drivenlthereby, a-carriageadapted to bring a said saw nto cooperative relation withithe materialto be sawed, an electrih feed motorto move the carriage, a transformerfor said saw motor, a 'coutrollergforsaid feed motor and said sawi'notor electrically con nectedto said transformer, means to obtain saidtransformer normal and abnormalsaw motor voltage, means for o ratingsaid carriage in. one direction whi e 'alow voltage is on said saw motorand in the opposite direction after abnormal voltage has been, appliedto the saw motor for an appreciable length of time and automatic meansfor again impressing normal voltage on said saw motor. v

5. The combination of an electric motor, a

carriage d i n thereby, 1 second electric direction and means forapplying a duty voltageis applied to the'dutyg motor when the carriageis 0 rated in one direction and normal voltage is applied to the dutymotor when the carriage is operated in the reverse direction.

7. The combination of a duty motor, a-tool actuated thereby, amovablecarriage, a

feed motor for' actuat' said carriage,

means for applying one vo tags to the duty motor when the carriage ismovinfijn one voltage to the duty motor for reversing the BEST AVAILABLECOP;

feed motor to move the carriage in the op-' posite direction.

8. The combination, of a duty motor, a tool actuated thereby, a movablecarriage adapted, when moving in one direction, to present work to saidtool, a feed motor for actuating said carriage, means for applying voltage above normal to the duty motoflmhen the carriage is presenting work.to said tool and for applying normal voltage to said motor when thecarriage is moving in the opposite direction. v

9. The combination of a duty motor, a tool actuated thereby, areciprocable carriage adapted, when moving in one direction, to

present work to said tool, a feed motor for reciprocating, saidcarriage, a transformer for impressing upon said duty motor nor- 'malmotor voltage when said carriage is moving the work away from said tooland means for connecting said duty motor directly to a line carryingvoltage higher than normal motor voltage when said carriage ispresenting work to said tool.

10. 'In a system of-the character described, I

the combination of a duty motor, a disk actuated thereby, a movablecarriage, a feed motor for actuating said carriage, projections on saidcarriage, a controller, contact devices on said controller adapted to beactuated by said projections, whereby said feed motor is automaticallyreversed when said carriage reaches the extremity of its movement ineither direction and the voltage on said duty' motor is normal orabnormal depending'upon the direction of movement-of said carriage. I

LOUIS H. THULLEN.

Witnesses:

E. HAYWARD FAIRBANKS, C. D. MoVar.

